Green’s Dictionary of Slang

a middleman, e.g. in espionage or in the transmission of bribes.

1976		Time 5 Apr. 23: The firm operated as a ‘cut-out,’ or front, for the FBI’s purchase of eavesdropping equipment.
1980		G. Liddy Will 172: The taking of material from the vault would be discovered and the fire engine traced to a cut-out buyer.
2001		N. Green Shooting Dr. Jack (2002) 143: You work through a broker, a cutout man, you never see the shooters.
2017		D. Winslow The Force [ebook] I take my taste from Michaels. It’s what I get for being the cutout, so two fucking lawyers don’t have to embarrass themselves by acknowledging to each other they’re for sale.
2023		A. Nette Orphan Road 13: A cut out for Vera Leigh, Loomis dealt with anything messy or illegal.